Heavy-duty stabilized camera head with camera position sensing
A panhead (1) having a counterbalance action suitable for heavy cameras or equipment, and provides instantaneous electronic measurements of head settings and position. The improved counterbalance utilizes a dual-tower dual-axis non-linear mechanism as well as position encoders indexed to each axis (7-13) of head movement. Potentiometer setting detectors are also indexed to settable adjustments to read and relay such adjustments, and an electronic display (25) conveys information regarding the current positions and settings of the camera head (1). A novel mounting system situated at the top of the head provides for fast and simple mounting and unmounting of equipment or a dutch roll head. In particular, a novel dovetail (19, 21) engagement mechanism swings a dovetail side down during detachment. In an embodiment of the invention, the dutch roll head can be remotely proportionally actuated by a user via a switch mountable to a handle used for panning and tilting of the pan head.
This invention relates generally to equipment for supporting optical equipment and, more particularly, relates to a camera head for pivotally supporting a camera in a counterbalanced manner.
BACKGROUND OF THE INVENTIONCameras have been and continue to be critical components in both motion picture and television feature production. An important criterion for the use of a camera in television or motion picture capture tasks is the ability to smoothly follow an action item, such as an athlete, with the camera. However, cameras usable in motion picture and television work are typically heavy and cumbersome to manipulate. For example, a standard television camera may weigh 100 pounds or more. Thus, in order for a camera to be manipulable so as to provide such smooth operation, it is desirable to balance the weight and inertia of the camera and to mitigate the effects of minor unintended forces on the camera by the operator.
In order to stabilize the motion of a camera on a camera head, it is typical to employ drag mechanisms. One such prior art drag mechanism is illustrated in U.S. Pat. No. 4,955,568 (“the '568 patent”) to O'Connor et al, entitled “Panhead For Camera,” which is assigned to the assignee of the present invention and is hereby incorporated by reference in its entirety for all that it teaches. In particular, the '568 patent illustrates an adjustable fluid drag mechanism. It is useful for camera operators to have ready access to data describing the various drag settings for the camera, so as to accurately adjust such settings and to be able to accurately reproduce a desired setting at a later time. However, the mechanism illustrated in the '568 patent does not provide for the rapid collection and display of measurement data relating to the drag forces set by the operator. Other prior art mechanisms have also not provided integral mechanisms for sensing drag settings and quickly conveying such settings to the camera operator in a unified way. Rather, prior art techniques have generally employed visual mechanical mechanisms that do not provide the level of accuracy, repeatability, and ease of use desirable in the motion picture industry.
Generally, counterbalance measures have been utilized to balance the weight of the camera about the tilt axis. An example of a spring-operated counterbalance technique is described in the '568 patent, previously incorporated by reference in its entirety. Other counterbalance techniques have been employed as well. For example, counterbalances using linear springs or cam and roller architectures have sometimes been employed.
However, prior art counterbalance techniques generally function well only for small to medium tilt angles. While the counterbalance mechanism disclosed in the '568 patent functions over a tilt angle of ±90° and desirably exerts a sinusoidal restoring torque, none of the prior art techniques, including that of the mechanism disclosed in the '568 patent, are adapted and ideally suited for heavier cameras. Many of the cameras in use today for motion picture and television filming work, however, may far exceed 200 pounds in weight. For that reason, a heavy-duty counterbalance mechanism adapted to accommodate the counterbalance loads produced by such equipment is needed.
Additionally, prior art mechanisms for attaching a camera or other equipment unit to a camera head are not suitable for use with heavy equipment. That is, they do not provide sufficient ease of attachment and detachment for cameras that are cumbersome due to extreme weight. For example, a typical sliding dovetail connection requires a user to slide a heavy object along a precise axis while holding the object level until support is achieved. Even systems that permit one side of the dovetail base to drop away for camera removal still require manual intervention by the user to force the dropping side down.
In addition, it is often desirable for a camera operator or film editor to know the position of the camera throughout a shot or sequence in order to reproduce a scene or to coordinate special effects with the actual footage taken. The prior art, however, has not included means by which the camera operator could readily ascertain and thereby reproduce the exact position of the tripod and camera.
Accordingly, it is a general object of the invention to provide an improved camera panhead that smoothly pans and tilts while allowing instantaneous capture and display of camera position and drag setting information. A more specific object is to provide a head that provides the instantaneous electronic capture and display of the camera position and movement.
It is a further object of the invention to provide an improved camera panhead that is able to provide nonlinear counterbalance action for heavy cameras or other equipment throughout a wide range of tilt angles.
It is a further object of the invention to provide a camera head that allows easy and accurate adjustment of the counterbalance and drag settings.
It is a further object of the invention to provide an improved camera head that allows for the natural and uncomplicated mounting and removal of heavy cameras or other equipment to the panhead.
SUMMARY OF THE INVENTIONThe invention embodies in general terms an improved camera panhead that provides counterbalance action suitable for heavy cameras or equipment, and that provides instantaneous electronic measurements of head settings and position. The improved counterbalance utilizes a novel dual-tower dual-axis non-linear mechanism to provide sufficient restoring force and integrity to support heavy camera equipment, while still being relatively lightweight. The improved camera head also provides high-accuracy absolute position rotary encoders indexed to each axis of head movement, as well as potentiometer setting detectors indexed to settable adjustments. In this manner, both camera positions and parameter adjustments may be electronically captured, recorded, and displayed to the user.
A conveniently placed electronic display conveys information regarding the current state of the camera head. In particular, a digital LCD graphical user interface is located on the head and displays information relating to the position of the head and the position of the head adjustment settings such as drag and counterbalance settings. The digital display is part of an electronics module that also contains various electrical inputs and outputs. A remote display module may be connected to the electronics module via a cable to remotely display to a user data relating to the head.
A mounting platform situated at the top of the head provides for fast and simple mounting and unmounting of heavy equipment. In particular, a novel dovetail engagement mechanism provides for compressive force by a movable dovetail side during attachment of the camera. However, the novel dovetail engagement mechanism also swings the dovetail side down and away from the dovetail platform during detachment to facilitate easy removal of the camera or other heavy equipment from a dovetail base.
A dutch roll head attachment is mountable upon the mounting platform and is adapted to receive the camera, thus providing an additional axis of camera movement as well as positional information.
An embodiment of the invention comprises a panhead for supporting equipment and providing movement from a vertical position to a tilt position, said panhead comprising, in combination, a tilt housing, a tilt drum defining a tilt axis, said tilt drum being mounted within said housing for rotation about said tilt axis, at least four springs, said springs forming at least two separate pairs of springs, mounted in substantially perpendicular planes to said tilt axis, a common axis disposed substantially parallel to the tilt axis, at least one mount for mounting one end of each of said springs pivotally along a common horizontal axis, said common axis lying below said tilt axis in a vertical plane containing said tilt axis, whereby the end of one spring in each pair of springs coupled to the common axis is mounted between the ends of the other pair of springs coupled to the common axis, the spring pair mountings to the common axis being staggered, and a plurality of mounts for coupling the opposite ends of each pair of said springs to the tilt drum for rotation therewith, said pairs of springs being mounted at an angle to a substantially vertical plane containing the tilt axis when said panhead is in said vertical position, whereby said springs exert a restoring torque when the tilt drum is tilted from said vertical position to said tilt position. An embodiment of the invention further comprises a vertical pan shaft defining a vertical pan axis, and a base housing for mounting said tilt housing on said vertical pan shaft for rotation about said vertical pan axis. An embodiment of the invention further comprises a first integral rotary sensor disposed within the tilt housing and adapted to sense rotation of the tilt drum about the tilt axis and output a first signal indicative of the rotation of the tilt drum about the tilt axis. An embodiment of the invention further comprising a second integral rotary sensor disposed within the base housing and adapted to sense rotation of the tilt housing about the pan axis and output a second signal indicative of the rotation of the tilt housing about the pan axis. An embodiment of the invention further comprises a display unit for displaying a first display related to the rotation of the tilt drum about the tilt axis and a second display related to the rotation of the tilt housing about the pan axis, wherein the first and second displays are derived from the first and second signals respectively. An embodiment of the invention further comprises a roll head mounted to the panhead for rotation of the supported equipment for rotation of the supported equipment about a roll axis, the display unit further comprising an input for receiving a third signal indicative of an amount of roll about the roll axis experienced by the roll head mounted to the panhead, and a third display related to the amount of roll about the roll axis experienced by the roll head, wherein the third display is derived from the third signal.
In an alternate embodiment of the invention comprises a panhead for supporting equipment and providing movement from a vertical position to a tilt position, said panhead comprising, in combination, a tilt housing, a tilt drum defining a tilt axis, said tilt drum being mounted within said housing for rotation about said tilt axis, at least four springs, said springs forming at least two separate pairs of springs, mounted in substantially perpendicular planes to said tilt axis, a common axis disposed substantially parallel to the tilt axis, at least one mount for mounting one end of each of said springs pivotally along a common horizontal axis, said common axis lying below said tilt axis in a vertical plane containing said tilt axis, whereby the end of one spring in each pair of springs coupled to the common axis is mounted between the ends of the other pair of springs coupled to the common axis, the spring pair mountings to the common axis being staggered, and a plurality of mounts for coupling the opposite ends of each pair of said springs to the tilt drum for rotation therewith, said pairs of springs being mounted at an angle to a substantially vertical plane containing the tilt axis when said panhead is in said vertical position, whereby said springs exert a restoring torque when the tilt drum is tilted from said vertical position to said tilt position, a vertical pan shaft defining a vertical pan axis, and a base housing for mounting said tilt housing on said vertical pan shaft for rotation about said vertical pan axis, the panhead further comprising a first integral rotary sensor disposed within the tilt housing and adapted to sense rotation of the tilt drum about the tilt axis and output a first signal indicative of the rotation of the tilt drum about the tilt axis, the panhead further comprising a second integral rotary sensor disposed within the base housing and adapted to sense rotation of the tilt housing about the pan axis and output a second signal indicative of the rotation of the tilt housing about the pan axis, the panhead further comprising a display unit for displaying a first display related to the rotation of the tilt drum about the tilt axis and a second display related to the rotation of the tilt housing about the pan axis, wherein the first and second displays are derived from the first and second signals respectively, the display unit further comprises a plurality of further displays for displaying at least an indication related to the restoring torque exerted about the tilt axis when the tilt drum is tilted from an equilibrium position.
In an alternate embodiment of the invention, a panhead for supporting equipment and providing movement from a vertical position to a tilt position comprises, in combination, a tilt housing, a tilt drum defining a tilt axis, said tilt drum being mounted within said housing for rotation about said tilt axis, at least four springs, said springs forming at least two separate pairs of springs, mounted in substantially perpendicular planes to said tilt axis, a common axis disposed substantially parallel to the tilt axis, at least one mount for mounting one end of each of said springs pivotally along a common horizontal axis, said common axis lying below said tilt axis in a vertical plane containing said tilt axis, whereby the end of one spring in each pair of springs coupled to the common axis is mounted between the ends of the other pair of springs coupled to the common axis, the spring pair mountings to the common axis being staggered, and a plurality of mounts for coupling the opposite ends of each pair of said springs to the tilt drum for rotation therewith, said pairs of springs being mounted at an angle to a substantially vertical plane containing the tilt axis when said panhead is in said vertical position, whereby said springs exert a restoring torque when the tilt drum is tilted from said vertical position to said tilt position, the panhead further comprising a vertical pan shaft defining a vertical pan axis, and a base housing for mounting said tilt housing on said vertical pan shaft for rotation about said vertical pan axis, the panhead further comprising a pan drag assembly for exerting a drag force against rotation of the housing on said vertical pan shaft about said vertical pan axis, the panhead further comprising a tilt drag assembly for exerting a drag force against rotation of the tilt drum, and a display unit for displaying an indication related to an amount of drag force exerted against rotation of the tilt drum about the tilt axis or the tilt housing about the pan axis. In another embodiment of the invention, the panhead further comprises a roll head mounted to the panhead for rotation of the supported equipment about a roll axis, the display unit further comprising a roll display for displaying an indication related to an amount of drag force exerted against rotation of the roll head about the roll axis.
Another embodiment of the invention further comprises a dovetail mount for retaining a removable dovetail rail, the dovetail mount being adapted to secure the removal dovetail rail to a panhead of an equipment supporting device, the dovetail mount comprising: a pair of opposed dovetail sides forming a dovetail track, at least one of said dovetail sides being movable; a movable locking lever; and an actuable coupling mechanism extending between the movable dovetail side and the lever; said locking lever being movable in a first direction for pressing the movable dovetail side toward the opposed dovetail side, thereby retaining the removable dovetail rail, said locking lever being movable in a second direction to move the movable dovetail side away from the opposed dovetail side in a horizontal plane, movement of the locking lever past a threshold point in the second direction further acting to lower the movable dovetail side through the horizontal plane, allowing the removable dovetail rail to be disengaged from the dovetail track. In another embodiment, the actuable coupling mechanism comprises a camming arrangement to lower the movable dovetail side through the horizontal plane.
Another embodiment of the invention comprises a dovetail mount for retaining a removable dovetail rail, the dovetail mount being adapted to secure the removal dovetail rail to a panhead of an equipment supporting device, the dovetail mount comprising: a pair of opposed dovetail sides forming a dovetail track, at least one of said dovetail sides being movable; a movable locking lever; and an actuable coupling mechanism extending between the movable dovetail side and the lever; said locking lever being movable in a first direction for pressing the movable dovetail side toward the opposed dovetail side, thereby retaining the removable dovetail rail, said locking lever being movable in a second direction to move the movable dovetail side away from the opposed dovetail side in a horizontal plane, movement of the locking lever past a threshold point in the second direction further acting to lower the movable dovetail side through the horizontal plane, allowing the removable dovetail rail to be disengaged from the dovetail track, the actuable coupling mechanism comprising at least one movable arm pivotably coupling the locking lever to the movable dovetail side at a first pivot axis, and the camming arrangement comprises a catch and at least one trip lever pivotably coupled at a second pivot axis, said trip lever being disposed to engage said catch as said locking lever is moved past said threshold point in the second direction, said trip lever rotating about said second pivot axis to exert a force on said movable dovetail side to rotate the movable dovetail side about said first pivot axis to lower the movable dovetail side through the horizontal plane. In another embodiment, the trip lever is pivotably coupled to the movable dovetail side.
Another embodiment of the invention a dovetail mount for retaining a removable dovetail rail, the dovetail mount being adapted to secure the removal dovetail rail to a panhead of an equipment supporting device, the dovetail mount comprising: a pair of opposed dovetail sides forming a dovetail track, at least one of said dovetail sides being movable; a movable locking lever; and an actuable coupling mechanism extending between the movable dovetail side and the lever; said locking lever being movable in a first direction for pressing the movable dovetail side toward the opposed dovetail side, thereby retaining the removable dovetail rail, said locking lever being movable in a second direction to move the movable dovetail side away from the opposed dovetail side in a horizontal plane, movement of the locking lever past a threshold point in the second direction further acting to lower the movable dovetail side through the horizontal plane, allowing the removable dovetail rail to be disengaged from the dovetail track, the actuable coupling mechanism comprising at least one movable arm pivotably coupling the locking lever to the movable dovetail side at a first pivot axis, and the camming arrangement comprises a catch and at least one trip lever pivotably coupled at a second pivot axis, said trip lever being disposed to engage said catch as said locking lever is moved past said threshold point in the second direction, said trip lever rotating about said second pivot axis to exert a force on said movable dovetail side to rotate the movable dovetail side about said first pivot axis to lower the movable dovetail side through the horizontal plane, the catch being secured to the movable dovetail side.
Another embodiment of the invention further comprises a dovetail mount for retaining a removable dovetail rail, the dovetail mount being adapted to secure the removal dovetail rail to a panhead of an equipment supporting device, the dovetail mount comprising: a pair of opposed dovetail sides forming a dovetail track, at least one of said dovetail sides being movable; a movable locking lever; and an actuable coupling mechanism extending between the movable dovetail side and the lever; said locking lever being movable in a first direction for pressing the movable dovetail side toward the opposed dovetail side, thereby retaining the removable dovetail rail, said locking lever being movable in a second direction to move the movable dovetail side away from the opposed dovetail side in a horizontal plane, movement of the locking lever past a threshold point in the second direction further acting to lower the movable dovetail side through the horizontal plane, allowing the removable dovetail rail to be disengaged from the dovetail track, the dovetail mount further comprising at least one pair of mating rack and pinion gears secured to the removable dovetail rail and the dovetail track, whereby the position of the removable dovetail rail within the dovetail track can be adjusted by rotating the pinion before fixing the removable dovetail rail to the dovetail track.
Another embodiment of the invention comprises a quickly detachable battery power source including at least one battery having two terminals for powering electric functions of a panhead, the battery power source comprising; first and second leads adapted to be electrically coupled to the battery terminals; a housing for holding at least one said battery, said housing having a first end and a second closed end; and a closure for placement at the first end of the housing after insertion of the at least one battery, such that prior to fixed placement of the cylindrical closure at the first end of the housing, a voltage difference is not measurable across the first and second leads, and a voltage difference is measurable across the first and second leads after fixed placement of the closure at the opening of the housing. In another embodiment of the invention, fixed placement of the closure at the first end of the housing requires application of first force along an axis of the housing, followed by application of a second force along an angular direction relative to the axis of the housing, whereby the closure resists removal forces applied along the axis of the housing. Another embodiment of the invention includes an electronic panhead display package for displaying a readout corresponding to at least one angular displacement associated with a panhead, comprising such a battery power source and further comprising a processing unit and a backup power source, so that if the cylindrical closure is removed from the cylindrical housing, the backup power source will supply electrical power temporarily to the processing unit.
Another embodiment of the invention comprises a method for coupling a battery power source to a panhead to power electrical functions of the panhead, the method comprising the steps of providing a battery power source having a housing and having a first lead disposed at an end face the housing and a second lead extending from a side surface of the housing, linearly advancing the end face into engagement with the panhead, and rotating the battery housing to engage the leads with electrical connections of the panhead.
Another embodiment of the invention comprises a dutch roll head for providing a roll function to a camera, the dutch roll head being remotely actuable by a user, comprising:a roll axle disposed along a roll axis; a motor connected to the roll axle for causing rotation thereof about the roll axis; and a user grip adapted for mounting on a handle, whereby the grip may be used to move the handle; and an electronic interface element mounted on the user grip linked to the motor via an electronic link and adapted to be actuated by said user, whereby when said user actuates the interface element by a given amount, a signal is transmitted via the electronic link to the motor causing the motor to effect a rotation of the roll axle in an amount proportional to the given amount by which the user actuates the interface element. Another embodiment of the invention comprises such a dutch roll head wherein the interface element is selected from the group consisting of a sliding switch, a rotary switch, and a toggle switch.
Additional features and advantages of the invention will be made apparent from the following detailed description of illustrative embodiments, which proceeds with reference to the accompanying figures.
While the appended claims will set forth the features of the present invention with particularity, the invention, together with its objects and advantages, may be best understood from the following detailed description taken in conjunction with the accompanying drawings of which:
Turning to the drawings, wherein like reference numerals refer to like elements, the invention is illustrated as being implemented in accordance with teachings of the invention in a panhead as shown in
A housing 11 covers mechanisms related to the pivoting of the panhead about a tilt axis 13, the mechanisms running substantially horizontally through the center or central region of housing 11. The motion of the head 1 about this axis is also sensed and damped as will be discussed hereinafter. Locking lever 17 is operable to lock the head to prevent movement about tilt axis 13.
Situated at the top of the head 1 are structures to facilitate the mounting of a camera or other equipment to the head 1. In particular, a dovetail base 19 is fixed to the housing 11, while a dovetail platform 21 is fixable to the dovetail base 19 via two dovetail sides, one of which 23 is visible in
It will be appreciated that the placement of a heavy camera atop the head 1 will create a significant downward force in the direction of pan axis 7 when the camera is situated directly over the tilt axis 13. It will be further appreciated that any deviation of the center of gravity of the camera from pan axis 7 will result in an increasing torsional load about tilt axis 13 as the deviation increases. Thus, when a camera or other instrument supported on the platform 21 (or a dutch head) is then tilted about the tilt axis 13, a significant and nonlinear restoring force is required to counterbalance the camera so that the operator is not required to constantly exert force to prevent the camera from pulling itself downward around tilt axis 13. In accordance with an important aspect of the invention, the head 1 is provided with a heavy-duty nonlinear counterbalance mechanism.
Referring to
Referring to
However, for large heavy cameras, such as those weighing 200 pounds or more, the counterbalance force that the springs 205 must exert becomes immense. This creates a need for very powerful springs, each capable of exerting a restoring force of approximately 1000 pounds or more, but the use of such powerful springs tends to place large loads on the structural components of the head such as the rods 211 supporting the trees 201, 203. Additionally, the force required to adjust the counterbalance force by adjusting the position of the common rod 213 is greatly increased generally in proportion to the increase in spring strength.
The solution of the present invention is to employ strong yet compact compression springs, adapted to meet the large loads imposed, and being disposed in a novel arrangement to avoid damage to other components of the head. In particular, in order to minimize the weight of the finished head, it is desirable to use hollow steel rods 211, 213, produced from 4130 heat-treatable alloy steel or other high strength steel or alloy. The reason for using hollow steel rods is that other lightweight metals such as aluminum typically do not possess the structural strength of heavier metals such as stainless steel, chrome molybdenum alloys, and other alloys.
Even so, in order to reduce the weight of the head while accommodating the structural loads imposed by the strong springs used, it is desirable to reduce the permissible size of the rods by arranging the spring loading to reduce the exerted rod bending moment. Referring to
Two support towers 215, 217 for the common rod 213 are provided, approximately symmetrically placed on rod 213, extending downward in the direction of pan axis 7. It will be appreciated that the dual tower arrangement is also particularly suitable for use in an application such as this, where extremely high force springs are utilized. The bending moment applied to the common rod 213 is reduced by providing the dual support towers 215, 217, thus reducing the necessary size and weight of the common rod 213. To readily adjust for equipment of varied weights, these towers are vertically adjustable to adjust the position of the common axis or rod 213. This way, the operator may adjust the counterbalance force provided (according to the basic principles set forth in the '568 patent, already incorporated herein by reference in its entirety).
The spring assemblies are arranged as shown, so that the support towers are placed between oppositely extending wiffle tree and spring assemblies, which are disposed at an angle with respect to pan axis 7. Additionally, the wiffle trees and support towers are disposed in a relationship that minimizes the bending moments, and, therefore, stresses along the shafts. More specifically, the wiffle tree pairings are identical, rather than mirror images of each other across the center of the head along the tilt axis as in the prior art. That is, the wiffle trees are disposed in a staggered fashion as opposed to symmetrically about a central support tower, as disclosed in the '568 patent. In this way, the two central wiffle tree assemblies place the greatest bending load on their respective wiffle tree support rods 211. However, unlike the prior art, the other wiffle tree assembly on each support rod 211 provides minimal additional bending load because each is placed adjacent a support point, i.e. end wall 207 or end wall 209. With respect to the loads experienced by common rod 213, the bending loads are also minimized by the illustrated configuration. In particular, lower wiffle tree supports 203 are placed so as to minimize the distance between them and any adjacent support points such as support towers 215, 217 or end walls 207, 209. In addition, the close spacing of opposing lower wiffle tree supports 203 minimizes the local twisting moment resulting from pairs of oppositely directed horizontal force components applied on rod 213 by adjacent lower wiffle tree support pairs. In other words, the staggered positioning of the wiffle tree supports 201, 203 along the respective support rods 211 and common rod 213 minimize the resulting bending moments exerted by the two centermost wiffle tree supports 201, 203.
Note that the foregoing discussion describes a preferred arrangement for two pairs of spring assemblies used in counterbalancing, however, the two pairs of spring assemblies may alternatively be arranged in another configuration. Exemplary alternative configurations are shown in
The pinion gear is attached to a common shaft 315 that also carries a handle 313 that may be manipulated by an operator. The handle also preferably further includes an exposed socket on a common axis with the shaft 315, allowing the handle to be alternatively turned via an electric screwdriver or other rotary tool. This feature may aid the operator when there is insufficient time to turn the handle by hand the required number of turns to provide the necessary counterbalance.
It will be appreciated that rotation of the handle 313 will cause a rotation of gears 301, 303, and a subsequent coordinated raising or lowering of support towers 215, 217. In turn, the raising or lowering of the towers compresses the springs 205 to a greater or lesser degree, providing varying degrees of nonlinear counterbalance force to counter the tilting of the head about tilt axis 13.
To provide a third degree of movement and adjustment, a dutch roll head may optionally be used in conjunction with the panhead. A dutch roll head rotates about a third axis, typically referred to as the roll axis. A roll axis is one that is substantially parallel with the camera sight line axis, although the two need not be co-linear.
According to an important feature of the invention, however, the center of gravity of the mounted camera and roll platform 405 is disposed along the roll axis 407. In this way, the equipment balance of the head 1 remains unaffected by the roll of the equipment mounted on the dutch roll head 401. In order to facilitate adjustment of the height of platform 405, both to assure necessary clearance with the base 403 and to place the center of gravity of the platform 405 and camera along the roll axis 407, the platform 405 is movable up and down in the direction of axis 415. The base 403 is illustrated as being slotted to permit rod 413 to be moved vertically. However, other techniques for allowing vertical movement may also be used. For example, the platform 405 may be vertically movable with respect to rod 413. In any case, the movement of the platform 405 alone or the platform 405 and rod 413 is linearly constrained, as along a dovetail mount or along a track made of two rods.
While alternative mechanisms may be used to allow vertical movement of the platform 405, a rack and pinion, screw, or other suitable mechanism is preferably employed to reduce the force needed to adjust the position of the camera and platform 405. Such mechanism may be hand-operated, such as via a crank or other actuator. Alternatively, the mechanism may be motorized, such as thru the use of an electric motor geared to controllably alter the vertical position of the camera and platform 405, as will be appreciated by those of skill in the art. An exemplary geared vertical adjustment mechanism is illustrated in
A handle 411 is preferably fixed to platform 405 via shaft 413, the shaft 413 being coaxial with roll axis 407 and usable to pivot the platform 405 about the roll axis 407. Within base 403, several mechanisms are preferably attached to shaft 413. In particular, it may be desirable to provide an adjustable counterbalance mechanism on shaft 413 to laterally counterbalance the camera weight using the same principles discussed above to provide counterbalance on the tilt axis. Such counterbalance will, however, typically not be required if the camera center of gravity is placed as described above. Additionally, a drag mechanism is preferably indexed to shaft 413 within base 403 so as to allow for smooth camera movement about the roll axis 407. These elements will be discussed in greater detail hereinafter. The base 403 may be fixed to the panhead using any suitable mechanism, but it is preferable that attachment be by way of the dovetail platform to be discussed in greater detail below.
The degree of roll attainable depends upon the dimensions of the camera, in that interference between the camera and the base 403 will determine the limits of travel. Base 403 preferably exposes other controls usable to affect the roll behavior of the camera. In particular, such controls preferably include a lock 417 to prevent roll movement of the camera about the roll axis, and a drag adjustment 419 to adjust the amount of drag about the roll axis 407. A mechanical drag indicator 421 may also be exposed on base 403, and/or an electrical output may supply the drag information along with counterbalance adjustment information if counterbalance is used, and encoded roll position information. If counterbalance is used, base 403 preferably also exposes a counterbalance adjustment control as discussed with respect to the tilt axis counterbalance mechanism.
An alternative dutch roll head arrangement is shown in
In order to further couple a roll head support 441 to the base 425, a fourth socket 443 is secured to the roll support 441 and fixed atop the vertical support tube 439 via the fourth socket 443, and via a clamping action provided by a clamping bolt 445. The roll head support 441 rotatably supports an axle 447 having a roll handle 449 optionally coupled thereto on one side. The handle 449 may be disposed in a hole in axle 447 and fixed in place via a set screw 451, although other attachments are envisioned. On the other side of the roll head support 441, the axle 447 is attached to a roll platform 453, to which is attached, via screws or otherwise, a camera base 455. A camera 457 is mounted to the camera base 455. It will be appreciated by those of skill in the art that dutch rotation or roll of the roll platform 453, camera base 455 and the camera 457 will occur about the axis 461 defined by axle 447. In this embodiment, an axis 459 including the center of gravity of the camera 457, the camera base 455 and the platform 453 is conveniently illustrated as coinciding with the sight line 459 of the camera. Thus, those of skill in the art will appreciate that it is desirable to align the axis 459, which includes the center of gravity, and, here, the sight line, with the dutch rotational axis 461.
Further, note that the vertical adjustment mechanisms described with respect to
An alternative roll platform adjustment mechanism is shown in
Referring now to
The grip 1701 is electrically connected to a motor 1705. A switch 1707 on the grip 1701 allows the user to actuate the motor in either direction, and preferably at a rate that is proportional to the user induced displacement of the switch 1707, such as by sliding, toggling, or rotation. The motor 1705 is geared to an axle 1711 at the roll axis, such as axle 413 of
Using the actuator grip as described above, a user can pan, tilt, and roll the camera package using only one hand. This provides a smoother camera operation and eases the task of the camera operator. Additionally, the user's other hand can then be used to actuate other desired functions, such as drag adjustment, axis locks, and so on.
The mechanisms for adjusting the drag on each axis will now be discussed. As mentioned previously, providing a certain amount of drag on a given axis of rotation will tend to smooth the movement about that axis, eliminating camera overshoot and unsteadiness. Because cameras and operators differ greatly, it is desirable to provide an adjustment mechanism whereby the amount of drag may be preset or modified. The '568 patent, already incorporated by reference in its entirety, discloses the basic principle of viscous drag mechanisms, and the reader is referred to that patent for a full discussion of such mechanisms. The present invention utilizes the basic principles set forth in that patent, but utilizes an improved mechanism to actuate the drag sectors.
Referring to
The individual elements 619 of each of the drag sector assemblies 603 are appropriately fixed relative to each element 619 in a given drag sector assembly 603 by rods and spacers 620 or other appropriate mechanism. The individual elements 619 in turn are interleavably related to the drag disc assembly 605. In turn, the drag sector assemblies 603 are actuated in a coordinated fashion by gears 609 which are manipulated by a user through a knob 621 or other mechanism. Thus, as the user turns the adjustment knob 621, the drag sector assemblies 603 become symmetrically more or less interleaved with the drag disc assembly 605 depending upon the direction in which the knob 621 is turned. Note that although a direct connection is shown between knob 621 and gear 609, any alternative actuating arrangement may be used. For example, the knob 621 may drive a worm, which drives a worm gear, which is geared to gear 609.
The spaces between stacked discs 617 of the drag disc assembly 605, between the stacked individual elements 619 of the drag sector assemblies 630, and between the stacked discs 619 and individual elements 619 are filled with a viscous fluid. A greater level of interleaving will create a stronger viscous drag on the drag disc assembly 605 and hence on the shaft 607. Likewise, a lesser degree of interleaving will lessen the amount of drag associated with the rotation of shaft 607. The reader is referred to the '568 patent and U.S. Pat. No. 3,822,769 to O'Connor, hereby incorporated by reference in its entirety for all that it teaches, for a fuller discussion of the drag-producing interaction and environment.
The gears 609 are coordinated by interceding gears, chain and cogs, or other suitable mechanism for coordinating their movement, so that the assemblies 603 move symmetrically with respect to disc 605. Although two drag sector assemblies 603 are shown for clarity, any number of such assemblies may be employed. In another embodiment, only one such drag sector assembly and one such disc 605 are provided for each axis. In this presently preferred embodiment, the drag sector assemblies 603 each comprise 23 sector pieces 619 with 22 spacer elements (see 620) located between the sector pieces 619, and each disc 605 comprises 22 disc elements 617 spaced apart by 21 spacer elements (not visible) along shaft 607.
Having described the mechanical aspects of the invention in detail above, the electrical features of the panhead according to the invention will now be discussed. In accordance with an important feature of the invention, the position of the panhead 1 with regard to the degree which the mounted equipment is rotated about the pan axis 7, and/or tilted about the tilt axis 13, and/or the dutch head roll axis 461 may be directly read by the user. In this way, a given shot may be recorded or read for later duplication, for example, or for special effects applied based upon a given position of the equipment. In overview, the electrical features provided facilitate the measurement and reporting of camera position and adjustment settings. Other electrical features such as backlighting for camera level indicators are also preferably provided. In order to electronically sense the position of the panhead 1, rotary encoders are positioned within housings 5 and 11 (and dutch roll head, if utilized), as will be discussed more fully hereinafter. The sensed positions are converted to electronic data digitally displayable on graphical user interface panel 25 (as shown, for example, in
More specifically, panel 501 comprises a power button or switch 505 for turning on and off the power to the electronics module 503. Another button or switch 507 is operable to turn on and off certain lights. Such lights may be, for example, back-lights, such as LEDs used to enhance the readability of liquid bubble level devices mounted on the head which are usable to level the camera on one or more axes.
Further, panel 501 also comprises display elements related to the position of each axis as well as the drag setting for each axis and any counterbalance setting for each axis. Thus, for example, row 509 displays information related to the roll axis, such as head angle 511 on the roll axis, drag setting 513 for the roll axis, and counterbalance setting 515 for the roll axis. A reset button 517 is preferably provided for each axis to allow the operator to set the current angle as zero, so that subsequent angle measurements may be taken from that point. The display rows for the tilt 519 and pan 529 axes expose the same features and functionality, keeping in mind that a given axis may omit certain features. For example, it will not be typical to provide a counterbalance or associated counterbalance adjustment reading for the pan axis, but such may be provided.
The LEMO connector ports exposed by the electronics module preferably include a 5 volt auxiliary power input 521, a computer output 523, a remote output 525, and a roll head input 527. Although batteries typically power the electronics module, the 5 volt auxiliary power input 521 allows the operator to optionally power the electronics module via an external 5 volt DC power source. The computer output 523 provides the information collected and displayed in the form of a digital data stream to be received by a separate computer through a serial port or otherwise, so that the positions and settings of the head may be tracked and stored in the computer. The remote output 525 outputs head position and setting data in a digital or analog form usable by a remote display module. This function allows the operator to attach a remote display module to the remote output 525 via a cable and to place the remote display module in a location where the operator may conveniently view and/or record all or some of the data available on the panel 501. For example, the operator may place the remote display module adjacent to the camera eyepiece via an adhesive or mechanical connection for convenient and instantaneous viewing of head data.
While those of skill in the art will readily appreciate how to configure the circuitry of the electronics module to provide the desired behavior, certain features will be expressly set forth for the convenience of the reader. The electronic components within the electronics module may be placed on separate circuit boards, but it has been found that the use of a single dual sided circuit board is more compact and robust. Furthermore, it is desirable to backlight the panel 501. It has been found that an ideal way to provide such backlight is to illuminate the ends of a plurality of fiber optical cables, and terminate the non-illuminated ends of such cables at the back of the LCD display that provides the display information at panel 501. While the electronics module may be mounted on any part of the head, it has been found that the most convenient location for mounting the module is on the main body above the joint between the stationary base 3 and the housing 5, as illustrated in
In order to sense the position of the drag sector assemblies 603, a potentiometer 611 is associated with the gears 609. In one exemplary arrangement, a gear 615 is fixed to the shaft 613 of the potentiometer 611. This gear 615 mates with one of the gears 609 so that rotation of gears 609 causes a rotation of the shaft 613 of the potentiometer 611. In this way, the resistance exhibited by the potentiometer 611 gives an indication of the current position of the drag sector assemblies 603, and hence of the level of drag currently experienced by shaft 607. In another embodiment, the shaft 613 of the potentiometer is directly attached to the shaft of a gear 609, providing a corresponding rather than simply proportional reading. The electrical outputs of the potentiometer 611 are supplied to the electronic module 503, for use in deriving a digital representation of the current drag.
The electronic module 503 also comprises two potentiometer adjustments for each drag assembly in order to adjust the indication of drag given so that it travels from at or near 0% for the minimum amount of drag applied, to at or near 100% for the maximum amount of drag applied. In particular, as those skilled in the art of electronics will appreciate, one factory settable potentiometer is provided to adjust the percentage indicated when the drag sector assemblies 603 are minimally interleaved, while a second factory settable potentiometer is provided to adjust the slope of the percentage indicated as a function of the amount of interleaving. In this way, the percentage of drag indicated on panel 501 can be adjusted so that minimal interleaving yields a reading at or near 0% while maximum interleaving yields a reading at or near 100%.
A drag mechanism such as that described above is placed on each axis, so that the shaft 607 is rotated coincident with rotation on the relevant axis. Likewise, the drag adjustment setting on each axis is relayed to the electronic module 503 and is displayed in the appropriate location on the panel 501.
The remaining mechanisms usable to collect data for display on panel 501 will now be discussed in greater detail. Turning first to
The gearing arrangement of
Within an embodiment of the invention, the position of the head itself is measured and displayed to the user via panel 501. In this case, it is desirable to use precision rotary encoders rather than simple resistance measurements because greater accuracy may thus be obtained. Exemplary rotary encoders are commercially available. For example, the High-Sensing Accuracy Optical Photo Interpreter, part number GP1A35RV, sold by SHARP ELECTRONICS may be used to encode the movement of an appropriately slotted disc.
A pick-up 805 having a slot 807 is situated such that the sides 809, 811 of the slot are in a straddling relationship with the disc 801. One or more light sources such as LEDs or laser diodes reside within one of the sides 809, while one or more light detection devices such as photodiodes or other devices reside in the other side 811. The light source and light detection devices are situated so that light from a light source in side 809 passing through a slot 803 is detected by a light detection device in the other side 811. In this manner, the motion of the disc is detected electronically and an indication of the motion is transmitted on leads 813. It is preferable that the disc 801 and pick-up 805 combination selected also detect the direction of movement of the disc 801. In addition, although the preferred encoding mechanism operates via light transmission, other systems, such as those that operate using reflectance rather than transmission may also be used. Also, the described encoders are absolute encoders as are preferable for best accuracy. However, other types of encoders such as relative encoders may also be used alternatively.
An encoder disc/pick-up combination such as that described above is preferably placed on each axis of movement for which it is desired to display position information. Preferably, position information is displayed for each axis, i.e. the roll, tilt, and pan axes.
The first annular cavity 907 contains an adjustable drag mechanism as discussed with respect to
A slotted encoding disc 911 such as the disc 801 of
Accordingly, as the camera is tilted, in turn tilting the tilting components of the head, shaft 903 rotates in registration with the camera, causing disc 911 to rotate as well. As disc 911 rotates, the slots of the disc alternatingly pass and block light within the pick-up 909, creating an electrical signal indicative of the motion of the camera about the tilt axis 13. As discussed above, this signal is conveyed via electrical leads to the electronics module 913, corresponding to module 503 of
Note that the various cavities defined within the head and roll head may be changed, so that for example, more of the cavity is defined by one piece than by another, and so on. The only matter of consequence is that such a cavity somehow be defined. Also, note that the relation between the cavities 907, 909 need not be as shown. For example, the cavities, and associated elements, may be disposed on opposite sides of the head, rather than on the same side, such that one end of the axle 903 is associated with the drag mechanism, while the other end of the axle 903 is associated with the rotary measurement mechanism. Similarly, a tilt brake and tilt lock if used may be disposed at whichever end of the shaft 903 is convenient, and need not be on the same side as each other.
In a similar fashion, the position information for the other axes is measured and conveyed to the electronics module 913 for display.
A plurality of bearings 1013, 1015, 1017 are preferably employed to minimize the friction of rotation and to bear the considerable weight of the camera and the upper portion of the head, all of which can rotate about axis 7. The bearings 1013 may be any suitable type, such as Timpkin tapered bearings, adapted to support both axial and radial loads. Bearings 1015 are preferably disposed to bear axial load associated with the central axle attachment between the upper housing 1011 and the base 1001. Suitable bearings for this purpose include any bearing capable of bearing the magnitude and direction of stress applied, such as Torrington thrust bearings. Bearings 1017 are situated so as to bear radial loads between base 1001 and the lower part of upper housing 1011. Note that the bearings 1015 and 1017 provide a balancing load for the preloaded the tapered bearings 1013 in the illustrated arrangement. As will appreciated by those of skill in the art, any other suitable number, type and arrangement of bearings may be used instead of the illustrated configuration.
The base defines two annular cavities 1021 and 1023. The first annular cavity 1021 contains an adjustable drag assembly 1003 similar in structure and operation to that described above with respect to the tilt axis, the adjustment position of which is measured and displayed as described above. Thus, the cavity 1021 additionally contains a suitable viscous fluid, such as one of the many silicon-based fluids familiar to those of skill in the art. The second annular cavity 1023 contains an encoder disc 1025 and pick-up 1009, operating in substantially the same manner as described above with respect to the tilt axis, to measure and relay the pan axis rotation position for display to the user. Note that in the illustrated embodiment, the pick-up 1009 rotates with the upper housing 1011, while the encoder disc 1025 remains fixed relative to the base 1001. However, those of skill in the art will appreciate that appropriate relative motion may also be achieved by fixing the pick-up 1009 relative to the base and allowing the disc 1025 to rotate with the upper housing 1011.
Note that a pan axis lock may also be employed to lock the rotation of the upper housing 1011 relative to the base 1001. This generally requires a moving locking piece fixed to the housing 1011 and a stationary locking piece fixed to the base 1001. Locking of the pan axis is effected by locking the moving and stationary locking pieces together. Typically, one locking piece will be a disc and the other a disc clamp or other locking mechanism.
The housing 1101 optionally defines a third annular cavity 1113, containing an adjustable counterbalance mechanism, preferably of the design described above or alternatively as described in the '568 patent. If a counterbalance mechanism is employed to counterbalance the camera about the roll axis, its setting is preferably detected, relayed and indicated to the user as described above with respect to the tilt axis. Note that since the roll head attachment is optional, the electrical signals relating to the damping, counterbalance, and position of the roll head are carried by a separate cable having a male LEMO connector to be plugged into port 527 of the electronics module 503. Note that the aforementioned features of the dutch roll head are preferably also included in an embodiment as illustrated in
As discussed above, the electronic features of the panhead typically receive electrical power from a portable battery pack that is affixed to the head or to the tripod or other support. An exemplary construction for the battery pack is illustrated in cross sectional view in
The pin 1211 in the first top 1203 serves to provide electrical contact between the bottom contact 1207 and the body of second top 1205. A central contact 1213 in first top 1203 makes electrical contact with the positive end of the series of batteries within holder 1201 when the pack is assembled as in
The fit and function of the battery pack are illustrated in perspective view in FIG. 13 for the convenience of the reader. Elements 1301, 1303, 1305, 1311, 1313, and 1315 correspond to elements 1201, 1203, 1205, 1211, 1213, and 1215 respectively of
Note that in either manner of changing out the battery pack from the panhead, power to the electronics module will be interrupted momentarily. For this reason, it is desirable that the electronics module incorporates a capacitor or other electrical energy storage device to provide a short period, such as thirty seconds, of reserve power during battery change. While the battery pack is preferably adapted to accommodate 2 “C” size cells, any other number and size of cells may equivalently be used.
Because the panhead and related components as described herein are generally intended for use with heavy cameras or other equipment, according to another feature of the invention, an improved mechanism for mounting the camera to the panhead is provided. In particular, it is difficult and inconvenient to be forced to slide a heavy camera or roll head mounted on a dovetail platform completely out of a dovetail base before being able to remove it. Even with dovetail bases that would allow a dovetail side to be forced down to permit camera removal, the operator is required to manually force the side down. Unfortunately, clearances are generally such that this is often difficult or impossible.
In an embodiment of the invention, a novel dovetail base is provided that allows an operator to automatically lower one dovetail side by simply moving a lever.
In particular, as lever 1509 is pushed in a clockwise direction, it exerts a pull force on first link 1521, pivoting lever 1523, to which it is hinged, about pivot 1525, thus exerting a leveraged pull force along dogbone 1527, which is hinged to lever 1525. Dogbone 1527 in turn pulls on and rotates link 1529 clockwise about pivot 1531. This motion causes symmetrical pulling motions by side pieces 1535 and 1533. With the left portion of the assembly as illustrated, the movement of dogbone 1527 causes link 1529 to pivot about pivot point 1531, causing a clamping or downward motion as viewed on side piece 1535 via short link 1537. This clamping motion is transmitted to the opposite side piece 1533 of the dovetail side 1501 by link 1545, which causes link 1563 to rotate about pivot 1543 and place a downward clamping force on side piece 1533 via short link 1539. In this way, the rotation of the lever 1509 clockwise will compress as dovetail side 1501 exerts a force against dovetail platform 1503, locking the camera in position with respect to the dovetail base 1561.
Conversely, moving the lever 1509 in a counterclockwise direction serves to move dovetail side 1501 away and downward from dovetail platform 1503, effectively allowing the camera and platform 1503 to be simply lifted off the base 1561. The mechanism by which this occurs is illustrated in greater detail in
According to one feature of the invention, the dovetail side 1601 physically moves outward and downward to allow the dovetail platform 1603 to be easily placed and located beneath the stationary dovetail side along the opposite edge of the dovetail platform 1603. In this way, as lever 1509 of
As can be seen in
The clockwise rotational force depends upon the pivot point 1617 of the trip lever 1611 being lower than the pivot point 1619 between side piece 1635 and dovetail side 1601. Theoretically, the force exerted along link lever 1611 can be resolved into two perpendicular components. One component 1621 is directed along the line between pivot points 1619 and 1617, and this component has no effect and produces no movement. The other component 1623 is perpendicular to the line between pivot points 1619 and 1617, and it is this component that produces the clockwise rotation that moves the side piece 1601 downward from platform 1603.
While the trip lever 1611 has been shown pivotably coupled to the side piece 1601 and the trip catch 1613 fixed to the base 1561, it will be appreciated by those of skill in the art that the trip lever could alternately be pivotably coupled to the base and the trip catch fixed to the side piece. Under such an arrangement, the trip lever could slide along the upper surface of the side piece until it engages the trip catch at which time continued force exertion would cause the side piece to pivot the dovetail side down and through the horizontal plane. In such an arrangement, the pivot axis of the trip lever would be disposed above, rather than below, the pivot axis of the side piece. These are but two examples of how such a camming arrangement may be incorporated to provide the lowering movement of the dovetail side. It is further within the invention, as will be appreciated by those of skill in the art, to actuate the dovetail side 1601 such that substantial lateral movement is not required before downward movement of the side 1601 commences.
Returning to
It will be appreciated that a new and novel camera panhead, rollhead, mounting system, and power system have been described herein. In view of the many possible embodiments to which the principles of this invention may be applied, it should be recognized that the embodiments described herein with respect to the drawing figures are meant to be illustrative only and should not be taken as limiting the scope of invention. For example, those of skill in the art will recognize that the illustrated embodiments can be modified in arrangement and detail without departing from the spirit of the invention. Therefore, the invention as described herein contemplates all such embodiments as may come within the scope of the claims and equivalents thereof.
Claims
1. A panhead for supporting equipment and providing movement from a vertical position to a tilt position, said panhead comprising, in combination,
- a tilt housing,
- a rotatable structure defining a tilt axis, said rotatable structure being mounted within said housing for rotation about said tilt axis,
- at least four springs, said springs forming at least a first pair of springs and a second separate pair of springs, said springs of said first pair of springs being mounted such that the springs are disposed substantially parallel to one another, said springs of said second pair of springs being disposed substantially parallel to one another, said at least four springs being mounted in planes substantially perpendicular to said tilt axis,
- a common axis disposed substantially parallel to the tilt axis, a horizontal plane including said common axis, said common axis and said tilt axis defining a vertical plane containing both axes,
- at least one mount for mounting one end of each of said springs pivotally along said common axis, the opposite ends of the springs being disposed on a same side of the horizontal plane, said opposite ends of said first pair being disposed one side of the vertical plane and said opposite ends of the second pair being disposed on the opposite side of the vertical plane, the ends of one spring in each pair of springs coupled to the common axis by said at least one mount being mounted between the ends of the other pair of springs coupled to the common axis, such that the ends of the spring pairs to the common axis are staggered, and
- a plurality of mounts for coupling the opposite ends of each pair of said springs to the rotatable structure for rotation therewith, said pairs of springs being mounted at an angle to a substantially vertical plane containing the tilt axis when said panhead is in said vertical position, whereby said springs exert a restoring torque when the rotatable structure is tilted from said vertical position to said tilt position.
2. The panhead according to claim 1 further comprising an adjustment gearing for controllably positioning the common axis relative to the tilt axis.
3. The panhead according to claim 2 further comprising a common axle oriented substantially along the common axis, the one end of said springs being coupled to said common axle, the adjustment gearing further comprising at least two rotatably mounted vertical threaded shafts, each threaded shaft having an axis of rotation, the axes of the threaded shafts being substantially fixed relative to the tilt axis, the threaded shafts being threadably coupled to said common axle whereby rotation of the threaded shafts moves the common axle to vary the distance between the common axis and the tilt axis.
4. The panhead according to claim 3 wherein the adjustment gearing further comprises a synchronizer for rotationally indexing each screw to the other.
5. The panhead according to claim 1 further comprising a tilt drag assembly for exerting a drag force against rotation of the rotatable structure tilt drum.
6. The panhead according to claim 1 further comprising a vertical pan shaft defining a vertical pan axis, and a base housing for mounting said tilt housing on said vertical pan shaft for rotation of said tilt housing about said vertical pan axis.
7. The panhead according to claim 6 further comprising a pan drag assembly for exerting a drag force against rotation of the tilt housing on said vertical pan shaft about said vertical pan axis.
8. The panhead according to claim 6 further comprising a first integral rotary sensor disposed within the tilt housing and adapted to sense rotation of the tilt drum about the tilt axis and output a first signal indicative of the rotation of the tilt drum about the tilt axis.
9. The panhead according to claim 8 further comprising a second integral rotary sensor disposed within the base housing and adapted to sense rotation of the tilt housing about the pan axis and output a second signal indicative of the rotation of the tilt housing about the pan axis.
10. The panhead according to claim 9 further comprising a display unit for displaying a first display related to the rotation of the tilt drum about the tilt axis and a second display related to the rotation of the tilt housing about the pan axis, wherein the first and second displays are derived from the first and second signals respectively.
11. The panhead according to claim 10 further comprising a roll head mounted to the panhead for rotation of the supported equipment for rotation of the supported equipment about a roll axis, the display unit further comprising an input for receiving a third signal indicative of an amount of roll about the roll axis experienced by the roll head mounted to the panhead, and a third display related to the amount of roll about the roll axis experienced by the roll head, wherein the third display is derived from the third signal.
12. The panhead according to claim 10 wherein the display unit further comprises a plurality of further displays for displaying at least an indication related to the restoring torque exerted about the tilt axis when the tilt drum is tilted from an equilibrium position.
13. The panhead according to claim 7 further comprising a tilt drag assembly for exerting a drag force against rotation of the tilt drum, and a display unit for displaying an indication related to an amount of drag force exerted against rotation of the tilt drum about the tilt axis or the tilt housing about the pan axis.
14. The panhead according to claim 13 further comprising a roll head mounted to the panhead for rotation of the supported equipment about a roll axis, the display unit further comprising a roll display for displaying an indication related to an amount of drag force exerted against rotation of the roll head about the roll axis.
15. A counterbalance for use in exerting a counterbalancing force when moved from a vertical position to a tilt position about a tilt axis, the counterbalance comprising:
- a rotatable structure that is rotatable about the tilt axis;
- a common axle that is not rotatable about the tilt axis, said common axle having a common axis which is parallel to the tilt axis;
- at least two common axle supports supporting the common axle;
- first and second lateral axes disposed along either side of a vertical plane containing said tilt axis, each said lateral axis being disposed parallel to but not collinear with the tilt axis, said first and second axes being disposed for rotation with said rotatable structure about the tilt axis;
- a first pair of compressive spring assemblies coupled both to the common axle through a first pair of couplings and to said first lateral axis;
- a second pair of compressive spring assemblies coupled both to the common axle through a second pair of couplings and to said second lateral axis, one of the first pair of couplings lying between the second pair of couplings along the common axle, and one of the second pair of couplings lying between the first pair of couplings along the common axle, such that the spring pair mountings to the common axis are staggered; and
- a first rotary sensor for sensing the rotation of the rotatable structure about the tilt axis, and for producing an electrical tilt output indicative of the amount and direction of rotation of the rotatable structure about the tilt axis.
16. The counterbalance according to claim 15 wherein the first lateral axis is disposed a first distance from the common axis, and the second lateral axis is disposed a seconddistance from the common axis, said the first and second distances being substantially equal in the vertical position, rotation of the rotatable structure from the vertical position to the tilt position lengthening one said distance and shortening the other said distance such that the compressive spring assemblies produce said counterbalancing force about the tilt axis, said counterbalance further comprising a counterbalance adjustment mechanism including an adjustment that moves the common axle towards or away from the tilt axis, adjusting the first and second distances to adjust the counterbalancing force exerted by the compressive spring assemblies.
17. The counterbalance according to claim 15 further comprising a tilt housing external to and enclosing the rotatable structure, the common axle, the first and second pairs of compressive spring assemblies, and said first rotary sensor.
18. The counterbalance according to claim 17 further comprising a base housing, and a pan axle on a pan axis about which the tilt housing may rotate, said base housing housing the pan axle.
19. The counterbalance according to claim 18, further comprising within the base housing a second rotary sensor for sensing the rotation of the tilt housing about the pan axis and for producing an electrical tilt output indicative of the amount of rotation of the tilt housing about the pan axis.
20. A counterbalance for use in exerting a counterbalancing force when moved from a vertical position to a tilt position about a tilt axis, the counterbalance comprising:
- a rotatable structure;
- a tilt axis within said rotatable structure;
- a common axle within said rotatable structure, said common axle having a common axis that is parallel to the tilt axis;
- first and second lateral axes disposed along either side of a vertical plane containing said tilt axis, each said lateral axis being disposed parallel to but not collinear with the tilt axis;
- a first pair of spring assemblies coupled both to the common axle through a first pair of couplings and at said first lateral axis; and
- a second pair of spring assemblies coupled both to the common axle through a second pair of couplings and at said second lateral axis, one of the first pair of couplings lying between the second pair of couplings along the common axle, and one of the second pair of couplings lying between the first pair of couplings along the common axle, such that the spring pair mountings to the common axis are staggered;
- one of either the common axle or the first and second lateral axes being rotatable about the tilt axis, the other being rotatably fixed relative to the tilt axis whereby said spring assemblies exert said counterbalancing force during such rotation.
21. The counterbalance of claim 20 wherein said common axle is rotatable about the tilt axis, and said first and second lateral axes are rotationally fixed relative to the tilt axis.
22. The counterbalance of claim 20 wherein said common axle is not rotatable about the tilt axis, and said first and second lateral axes are rotatable about the tilt axis.
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Type: Grant
Filed: Apr 20, 2002
Date of Patent: Oct 30, 2007
Patent Publication Number: 20040113033
Assignee: Camera Dynamics Inc. (New York, NY)
Inventor: Joel W. Johnson (Newport Beach, CA)
Primary Examiner: Amy J Sterling
Attorney: Leydig, Voit & Mayer, Ltd.
Application Number: 10/475,636
International Classification: F16M 11/14 (20060101);
